The objective of this research is to improve our understanding of the role of membrane macromolecules in membrane function and more specifically to elucidate the role of specific macromolecules in ion flux in synapse membranes and the coupling of cholinergic receptors to ion flux in muscle surface membranes. Three experimental models will be employed: 1. Synaptic membranes isolated from cortical synapses of rats undergoing electroconvulsive shock. 2. Synaptic and microsomal membranes of chick optic tectum follow visual deprivation or enucleation. 3. Surface membranes isolated from normal and denervated muscle. In all three models protein, phospholipid, and carbohydrate constituents will be defined. The major emphasis will be on characterizing the phosphorylation of endogenous membrane proteins using both the endogenous as well as exogenous protein kinases. Substrate specificity, solubilization of the protein kinase, and the role of cyclic nucleotides and various neurotransmitters will be used to determine the potential role of membrane phosphorylation in modulating ion flux in enriched membrane fractions.